U.S. Pat. Nos. 1,642,897 and 2,087,228 show and describe conventional tire flaps which are used in conjunction with inflatable innertubes for protecting the tube against chafing by the wheel rim on which the tire and inflatable tube are mounted. Such flaps are only used as a cushion for protecting the innertube and are, therefore, not required to be impervious to fluids since they are not relied on to maintain inflation of the tire. Very narrow and loosely fitting flaps are employed in the wells of spoked wheel rims of bicycles and motorcycles to cushion and protect the innertubes of the tube-type tires against chafing or piercing by the spokes which are secured in openings formed in the wells of the wheel rims. Such loosely fitting flaps do not adequately seal the spoke openings in the wheel rim under low inflation pressure and are, therefore, unsuitable. This may be one of the reasons why conventional tubeless pneumatic tires have not been used on motorcycles in the past. In any case, the leakage of air through the openings in which the spokes are fastened is a big problem.
Special wheel rims have recently been developed for motorcycles to accommodate conventional tubeless tires. These special rims are designed to resemble conventional spoked wheel rims normally used on motorcycles and have rigid, radially oriented spoke-like arms which connect the outer wheel rim, on which the tire is mounted to the hub that is used in mounting the wheel rim to the axle of the motorcycle. The support arms are integrally cast with the hub and wheel rim to eliminate any openings through which air can leak and cause deflation of the tire. However, motorcyclists with conventional spoked-wheel rims are still unable to use conventional tubeless tires. The invention is directed to the solution of this problem by the provision of a device which allows the utilization of tubeless tires with conventional spoked wheel rims of a motorcycle.
Briefly stated, the invention is in a shield for sealing the cavity of a tubeless tire from the ambient atmosphere when the tire is mounted and inflated on a conventional, spoked wheel rim. The shield comprises an elastic, fluid impervious annulus which is designed to matingly conform to the well and base of a conventional spoked wheel rim and sealingly engage the beads of the tire even under low inflation pressures, thereby forming with the fluid impervious innerliner of the tire, an airtight chamber in which the proper air pressure can be maintained within the tire.